Here's a similar already answered question by u/Aethelric https://www.reddit.com/r/AskHistorians/comments/1v6dkz/how_did_medieval_outlaws_stay_outlawed_ie/
Edit: And another thread answered by u/sunagainstgold
https://www.reddit.com/r/AskHistorians/comments/6o066q/in_fantasy_books_bandits_seem_to_be_a_very_common/